La surveillance épidémiologique du risque de cancer

La santé fait partie intégrante du bien être. Certaines maladies bénignes sont faciles à supporter, surtout si elles durent quelques jours seulement. En revanche, d'autres maladies sévères sont lourdes, tant sur le plan individuel que collectif. Le cancer est l'une d'entre elles ; les risques de mortalité sont variables selon l'organe touché, mais, dans tous les cas, une prise en charge par le corps médical s'impose durant des temps longs, souvent plusieurs années. Aussi, des réseaux de surveillance, où médecins et géographes collaborent, ont-ils vu le jour pour mieux cerner les causes de ce fléau ; et, peut-être, en réduire le taux d'incidence1

Age-period-cohort modelling of non-Hodgkin's lymphoma incidence in a French region: a period effect compatible with an environmental exposure

<p>Abstract</p> <p>Background</p> <p>The incidence of non-Hodgkin's lymphoma (NHL) has risen steadily during the last few decades in all geographic regions covered by cancer registration for reasons that remain unknown. The aims of this study were to assess the relative contributions of age, period and cohort effects to NHL incidence patterns and therefore to provide clues to explain the increasing incidence.</p> <p>Methods</p> <p>Population and NHL incidence data were provided for the Doubs region (France) during the 1980-2005 period. NHL counts and person-years were tabulated into one-year classes by age (from 20 to 89) and calendar time period. Age-period-cohort models with parametric smooth functions (natural splines) were fitted to the data by assuming a Poisson distribution for the observed number of NHL cases.</p> <p>Results</p> <p>The age-standardised incidence rate increased from 4.7 in 1980 to 11.9 per 100,000 person-years at risk in 1992 (corresponding to a 2.5-fold increase) and stabilised afterwards (11.1 per 100,000 in 2005). Age effects showed a steadily increasing slope up to the age of 80 and levelled off for older ages. Large period curvature effects, both adjusted for cohort effects and non-adjusted (p < 10^-4and p < 10^-5, respectively), showed departure from linear periodic trends; period effects jumped markedly in 1983 and stabilised in 1992 after a 2.4-fold increase (compared to the 1980 period). In both the age-period-cohort model and the age-cohort model, cohort curvature effects were not statistically significant (p = 0.46 and p = 0.08, respectively).</p> <p>Conclusions</p> <p>The increased NHL incidence in the Doubs region is mostly dependent on factors associated with age and calendar periods instead of cohorts. We found evidence for a levelling off in both incidence rates and period effects beginning in 1992. It is unlikely that the changes in classification (which occurred after 1995) and the improvements of diagnostic accuracy could largely account for the 1983-1992 period-effect increase, giving way to an increased exposure to widely distributed risk factors including persistent organic pollutants and pesticides. Continued NHL incidence and careful analysis of period effects are of utmost importance to elucidate the enigmatic epidemiology of NHL.</p

Environnement infectieux et toxique et cancer Mécanismes -diagnostic –prévention.

International audienc

[Epidemiology of urogenital cancers in France]

International audienceEstimates of cancer incidence and mortality in France as well as survival data are published by the cancer registry network (Francim). In 2000, the number of new cancer cases was almost 280,000 in France. This number has been gradually increasing, partly due to population aging. The proportion of urological cancers is increasing as well, as a consequence of the marked increase in number of prostate cancers. The estimated number of new cases for the 4 main urological cancers in 2000 reached 61,174, distributed as follows: 40,310 prostate cancers, 10,771 bladder cancers, 8,293 kidney cancers and 1,800 testis cancers. Urological tumours represented at the time 22% of new cancer cases in France: 35% of male cancers (56,402 /161,025) and 4% of female cancers (4,772/117,228). The relative five-year survival for prostate cancers is high: 80%. It is below that of testis cancers (95% after 5 years), but higher than that of kidney cancers (64% in men and 63% in women after five years). Of all urological cancers, bladder cancers have the worst prognosis, since the relative five-year survival is 60% in men and especially 50% in women

Variation in relative survival of thyroid cancers in Europe: results from the analysis on 21 countries over the period 1983-1994 (EUROCARE-3 study).

International audienceWe described the relative survival of thyroid cancer cases diagnosed in Europe during the period 1990-1994 and analysed time trends in relative survival during the period 1983-1994 using the EUROCARE-3 database. Relative survival of thyroid cancers is one of the highest amongst cancer sites, with age-standardised relative survival rates of 74% in men and 82% in women over the period 1990-1994, with marked differences between countries. The higher relative survival rates are observed in Scandinavian countries and the lower rates are observed in the UK and the countries of Eastern Europe. Relative survival is higher in women than in men, and decreases with age whatever the histological group. There are significant differences in relative survival according to histological type. Relative survival has slightly increased over the period 1983-1994 only when all histological types have been considered together. Time trend was, however, non-existent when the different histological groups were taken into account except during the most recent period of observation. One possible explanation for the differences in relative survival between countries and sex may probably be found in the changes in thyroid classification and diagnosis techniques. When these changes are not homogeneous, the distribution of thyroid cancers by histology and by stage at diagnosis may be very different. The only way to understand these differences is to conduct specific studies including a description of stage at diagnosis, diagnosis procedures used for staging and details of treatment

Incidence des hémopathies lymphoïdes: Intérêt de l'utilisation de typologies territoriales pour l'étude des déterminants sociaux

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The performance of multiple imputation for missing covariate data within the context of regression relative survival analysis.

International audienceRelative survival assesses the effects of prognostic factors on disease-specific mortality when the cause of death is uncertain or unavailable. It provides an estimate of patients' survival, allowing for the effects of other independent causes of death. Regression-based relative survival models are commonly used in population-based studies to model the effects of some prognostic factors and to estimate net survival. Most often, studies focus on routinely collected prognostic factors for which the proportion of missing values is usually low (around 5 per cent). However, in some cases, additional factors are collected with a greater proportion of missingness. In the present article, we systematically assess the performance of multiple imputation in regression analysis of relative survival through a series of simulation experiments. According to the assumptions concerning the missingness mechanism (completely at random, at random, and not at random) and the missingness pattern (monotone, non-monotone), several strategies were considered and compared: all cases analysis, complete cases analysis, missing data indicator analysis, and multiple imputation by chained equations (MICE) analysis. We showed that MICE performs well in estimating the hazard ratios and the baseline hazard function when the missing mechanism is missing at random (MAR) conditionally on the vital status. In the situations where the missing mechanism was not MAR conditionally on vital status, complete case behaves consistently. As illustration, we used data of the French Cancer Registries on relative survival of patients with colorectal cancer